Objectives: To compare the perioperative respiratory adverse events between using laryngeal mask airway and endotracheal tube in preterm neonates receiving general anesthesia for hernia surgery.

The participant patients will be randomly allocated into two groups: the laryngeal mask airway group (LMA group) and endotracheal tube group (ETT group). Masking ventilation with sevoflurane will be used for anesthesia induction till the adequate anesthetic depth. Intubation with laryngeal mask airway (LMA) or endotracheal tube (ETT) will be done as allocated group. After the surgery completed and the patient wakened up, the anesthesiologist will remove the LMA or ETT according to the clinical criteria for extubation.

Inclusion Criteria:

• preterm neonates (gestational age < 37 weeks) in our neonatal ward scheduled to receive unilateral or bilateral inguinal hernia repair surgery, and whose body weight > 2000g at surgery

Exclusion Criteria:

• emergent surgery, infants who was intubated before surgery, long-term oxygen or mechanical ventilation dependence, severe congenital cardiopulmonary disease, lacking of birth history, combination with other major surgery, postmenstrual age > 52 weeks at surgery